Measurements of electron dynamics during lower hybrid current drive

The method of oblique-incidence electron cyclotron wave transmission is studied in a lower hybrid driven tokamak plasma. Cyclotron wave transmission measures the asymmetry in the suprathermal electron parallel-momentum distribution which may be integrated to obtain a measure of the suprathermal electron current. Questions of resolution, sensitivity, and technique are addressed experimentally. The results indicate that cyclotron wave transmission is well suited for studies of electron velocity-space phenomena and may be used to detect small perturbations in the suprathermal current. (Author)